alt.energy.renewable

-> The air that is compressed and put into the storage tank that, I assume,
-> is mounted in the vehicle, from where does this air come?

-> Is the air modified in any fashion before it is put in the tank?
-> Is there any water vapor in the air?

-> What is the volume of the expansion space at TDC (Top Dead Center)?
-> What is the volume of the expansion space at BDC (Bottom Dead Center)?

-> What is the temperature of the air at TDC?
-> What is the temperature of the air at BDC?

Are you asking me or Tata?

Air normally comes from the atmosphere. When air is compressed, and
allowed to cool back to room temperature, any water vapour in it
usually condenses. So the air has to be "modified" by removing the
water vapour if condensation, corrosion, etc., are to be avoided. This
is standard technology, done, for example, at every filling station for
scuba tanks.

I vaguely imagine a double- or triple-expansion engine with a volume
ratio of something like 1:100. I don't know what Tata's plans are. The
inlet temperature of the air would be ambient, if no throttling is
done. Ideally, the exhaust temperature would be ambient too, but this
would require a heat exchanger to take heat from the environment to
keep the air warm as it expands.

What would *your* answers to these questions be?

dow